Background and Purpose: Left ventricular hypertrophy (LVH) is a major risk factor for cardiovascular morbidity and mortality. Criteria differentiating LVH from"normal" left ventricular mass have been derived from the population distributions of largely Caucasian groups. At any given LV mass, whether normal or elevated, there is a spectrum of LV wall thickness relative to chamber size. Clinically, measurement of this "relative wall thickness" (RWT) provides further prognostic information in addition to LV mass. Significant increases in cardiovascular events, deaths, and all-cause mortality are observed in whites with abnormally elevated RWT (>0.45), independent of mass measurements. Although electrocardiography (ECG) in blacks reveals significantly increased prevalence of voltage criteria for LVH, the prevalence of LV mass criteria for hypertrophy in blacks is the same as comparable white populations. However, blacks as a group have higher RWT than whites, irrespective of the presence or severity of hypertension or the presence of mass criteria for LVH. This inherent difference in the ventricular structure of blacks brings into question the use of traditional mass criteria for hypertrophy in this population. Relative wall thickness (RWT) of the LV is an important risk factor, but its epidemiology in blacks and in particular its relationship to other clinical predictors and electrocardiographic voltage characteristics is currently not known. The study proposed by this CAP project will address these vital issues in a large black cohort. The study will: (1) determine ECG voltage criteria that correlate best with RWT in blacks; (2) determine clinical predictors of RWT in a black population and (3) develop a multivariate clinical prediction rule for RWT in blacks. Methods: A cohort of black men and women with newly-diagnosed coronary artery disease (CAD), but without prior cardiac events, will be recruited. Accrual of clinical and laboratory data will be more complete and less subject to bias in a prospective cohort than it would through retrospective study. We have selected to focus on patients with CAD because a greater diversity of risk factors is likely in a population of patients with known coronary artery disease. The expected event rate in this group is much higher than for patients with hypertension or diabetes alone, and makes a future prospective cohort survival study feasible within a reasonable time from. This will be a major focus on the CAP's future investigative efforts, for which the current proposed study will provide an important foundation. This second step will entail prospective follow-up of event-free survival of a population with previously well-defined "exposure" RWT data. Subjects will undergo a complete clinical evaluation, including a directed history, physical examination, and ECG. A complete 2D and Doppler echocardiographic study will be performed at that time, from which baseline RWT and LV mass will be obtained. Clinical covariates to be assessed include detailed history of hypertension, diabetes hyperlipidemia,, peripheral vascular disease and smoking. The results of the coronary angiography and hemodynamics will also be coded and retained. All medications will be noted. Phlebotomy for fasting lipid panel, glucose, and hemoglobin A1C will be performed. A cross-sectional analysis of the clinical and ECG characteristics predictive of echocardiographic relative wall thickness is proposed. Univariate analyses will be conducted to establish the association between candidate predictor variables with RWT as a continuous variable using linear regression and analysis of variance (ANOVA) techniques. Multivariate linear regression will subsequently be used to identify independent predictors of RWT and to develop a parsimonious predictive model. Secondary analysis of RWT as a dichotomous variable will be performed with logistic regression techniques, using the currently-accepted cut-point of 0.45 as well as selected alternative cut points.